1. Field of the Invention
The present invention relates to a power tool having a mode switching device for switching between a plurality of driving modes.
2. Description of the Related Art
Japanese Utility Model Publication No. 2-30168 discloses an electric hammer drill having a speed changing clutch actuating mechanism capable of switching the rotational speed of a spindle between high-speed mode and low-speed mode. This known hammer drill includes a mode switching device that converts rotation of a switching lever turned by user's manual operation into linear motion of a sliding member via an eccentric pin and transmits the linear motion to a clutch mechanism. A torsion spring is disposed between the eccentric pin and the sliding member. The torsion spring is substantially integrally formed with the sliding member. When engagement of a driving-side clutch member and a driven-side clutch member of the clutch mechanism is interrupted during turning operation of the switching lever for mode change, the torsion spring is elastically deformed and builds up the spring force. Thereafter, when the interruption is resolved, the sliding member is caused to linearly move by the accumulated biasing force of the torsion spring, so that the clutch mechanism is engaged.
With the above-mentioned construction in which the torsion spring is disposed astride between the eccentric pin and the sliding member, the arms of the torsion spring increase in length, so that the torsion spring increases in size. Further, the eccentric pin and the sliding member are disposed apart from each other, so that a wider installation space is required. Therefore, the known mode switching device needs further improvement in these points.